Mark McCall, the Saracens director of rugby, has warned Clermont Auvergne that it will not be another case of “men against boys” when his side rejoin Heineken Cup battle with the French powerhouses in the semi-final at Twickenham on Saturday.

McCall reflected at Saracens’ St Albans training ground that the quarter-final at Vicarage Road two years ago, when Clermont steamrollered his side 22-3, effectively marked the turning point in the club’s approach, making them realise they had to bulk up to take on France’s finest.

Now, having improved to make the semi-final last season, McCall is adamant that Saracens, leading the way for English rugby both domestically and in the Heineken Cup, are equipped, physically and mentally, to go one step further and beat the team who have threatened for so long to rule the European game.

“We would hold our hands up and say that day two years ago was a little bit men against boys, but it’s not going to be like that this weekend,” McCall said, as he announced that Owen Farrell, their sole points scorer in that 2012 game, had recovered from his foot injury and would orchestrate Saracens’ challenge.

McCall likened the experience that year to playing with “one hand tied behind our backs”, such was the disparity between the power of the two sides.

“We were a bit lightweight, fighting against people who were more powerful, more explosive, bigger,” he said. “But we changed a lot after that.

"We changed the way we went about things in the strength and conditioning department, changed the people that we had here and changed our recruitment policy.

“When we first came, we set out to be the fittest team around. Take someone like Will Fraser [a flanker]. He was 99kg and as brave and tough as they come, yet he was playing against people 10kg heavier.

"So we changed things. Now Will is 108kg. It’s not just weight he’s put on; it’s the right kind of weight. He is more powerful, more explosive, quicker. He is a better rugby player.”

Allied to this, pointed out McCall, was the appointment of Philip Morrow, who had been head of fitness with Ireland. “It was the best signing we have made because he changed everything from top to bottom from the performance side of things.”

The result, McCall said, had been the flowering of a team who challenged Toulon “in a six-point game with 12 minutes left” in last season’s semi and have progressed significantly since, leading the Premiership by nine points and being England’s last hope in the Heineken Cup.

“We know what we are up against but we think we can go one better,” McCall said. “We’re playing better, our game has evolved, we have players in form and we’re going into the game with much more confidence than last year’s semi-final, when I think that we were a little bit happy to be there.”

Farrell has fully recovered from the foot injury which he suffered during the win over Northampton earlier this month. “He’s unbelievably mature, reacts brilliantly, steers the team really well and we’re lucky to have him,” was McCall’s tribute.

If Saturday’s game was being played at Clermont’s Marcel Michelin fortress, where they are unbeaten for 76 games, this would be a very different prospect, but Saracens fancy their chances at HQ against a team who have lost nine times on the road in the Top 14 this season and have a reputation for frailty in the biggest games.

“You would have thought that they have been the best squad and the best team in Europe for a long time and yet they haven’t won the Heineken Cup and have only won the Top 14 once,” said McCall, identifying flying New Zealand wing Sitiveni Sivivatu as the major danger.

“We know how difficult it is to win things but we’ve got ourselves into a cracking situation and need to take advantage of it. Just to get to the semi-finals for this group of players is not enough any more. We need to kick on and win something.” Perhaps even two trophies? “Standing here right now, I’m sure you would settle for one,” McCall smiled.